The present invention relates to the field of color displays, and more specifically, to a method and apparatus for manipulating subpixels contained within a serial data stream to form a displayed image.
In an aircraft, pilots obtain critical information from instruments that include color displays. Certain color displays use a quad subpixel arrangement while other displays use a striped subpixel arrangement.
A quad-subpixel display 100 is depicted in FIG. 1 and includes pixels 110, where each pixel is comprised on a red subpixel 111, a first green subpixel 112, a blue subpixel 113, and a second green subpixel 114. This type of display has been developed specifically for military applications where it is desirable to double the display resolution for monochrome operation such as during the display of night vision imagery.
FIG. 2 shows a striped-subpixel display 200 that includes pixels 210, where each pixel is comprised on a red subpixel 211, a green subpixel 212, and a blue subpixel 213. The striped-subpixel display is very similar to the Sony Trinitron(copyright) color television and has been developed extensively for commercial uses.
In the years following the Cold War, and especially during the present, commercial display technology has surpassed military display technology. For example, the typical laptop computer available commercially has a greater resolution along with an attendant higher number of pixels than many of the most advanced military displays in service.
A significant amount of aircraft specific graphics symbology, and more particularly military specific graphics symbology, has been developed and continues to be used on aircraft displays. One specific military unique display includes a quad-subpixel arrangement. It is desirable to replace this quad-subpixel display on certain aircraft with the newer striped-subpixel display. However, changing the software underlying to this graphic symbology usually entails a long and costly development process.
There is a need in the art for a hardware apparatus and method that can intercept a digital data stream intended for a quad-subpixel display and reformat it into a digital data stream suitable for a striped-subpixel color display without introducing a significant time delay into the resultant displayed image. Such an apparatus and method will allow the re-use of previously developed military symbology without software modification in an existing aircraft display processor.
I have discovered that it is possible to process a digital data stream intended for a quad-subpixel display, for example a serial digital stream, by padding extra data values to the serial digital stream in real time. The resulting intermediate digital stream containing pad data, if displayed, would show a distorted picture. However, I have further discovered that the distortion can be removed by use of a commercially available resizing engine.
My invention extracts color and intensity information, for each subpixel in a digital data stream, representing a quad-subpixel color image and processes and redirects this information into an intermediate pixel memory. Additional data values are interspersed between the input values to pad the intermediate pixel memory; for example, the odd input lines do not include an xe2x80x98bluexe2x80x99 sub pixel data. After processing, the intermediate pixel memory contains data that can be used as an input to a display resizing engine such as a Genesis(copyright) chip, which in turn provides a digital data stream output that is suitable to drive a striped subpixel display. Advantageously, my invention can resize an alternate bit map from the intermediate pixel memory in order to account for the potentially different quantity of pixels in the quad subpixel (m times n) versus the striped subpixel (x times y) display.
In one specific illustrative embodiment of my invention, the extra data values padded into the data stream have a zero value. In a second illustrative embodiment, the padded zero values are replaced with average intensity values.